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Query: UNIPROT:P01178 (
oxytocin
)
15,767
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
cDNA clones encoding two members of the vasotocin hormone precursor gene family have been isolated from the white sucker Catostomus commersoni. The hormone is encoded by at least two distinct genes, both of which are expressed, as indicated by Northern blot analysis. Genomic DNA amplified by the polymerase chain reaction has been used to define exon-intron boundaries. Both vasotocin genes contain introns in positions corresponding to those found in the gene of their mammalian counterpart vasopressin. The predicted vasotocin precursors show a surprising degree of sequence divergence, amounting to 45% at the amino acid level, of which only approximately half can be accounted for by conservative amino acid changes. The precursors include a hormone moiety followed by a putative
neurophysin
sequence that is longer at the C-terminus by a tract of some 30 amino acids by comparison to their mammalian counterpart. Each of these sequences contains a
leucine
-rich core segment resembling that found in copeptin, a glycopeptide moiety present in mammalian vasopressin precursors.
...
PMID:Vasotocin genes of the teleost fish Catostomus commersoni: gene structure, exon-intron boundary, and hormone precursor organization. 197 Jul 42
The response to small peptides such as Arg-vasopressin,
oxytocin
and tachykinins was investigated in cultured porcine aortic endothelial cells. The production of endothelium-derived nitric oxide was assessed indirectly by the accumulation of cyclic GMP, a response that is due to the increased activity of soluble guanylate cyclase of the endothelial cells after release of the mediator. Arg-vasopressin,
oxytocin
, substance P and physalae-min (an analog of substance P, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-
Leu
-Met-NH2) markedly and transiently stimulated the production of cyclic GMP without affecting that of cyclic AMP. Treatment of endothelial cells with either hemoglobin or methylene blue reduced significantly both the basal and stimulated level of cyclic GMP. The production of cyclic GMP evoked by Arg-vasopressin and substance P was inhibited selectively by NG-monomethyl-L-arginine but not by its D-enantiomer. The neurohypophyseal hormones and related peptides stimulated the accumulation of cyclic GMP in a concentration-dependent manner, with the following relative order of potency:
oxytocin
greater than Lys-vasopressin greater than Arg-vasopressin much greater than [deamino-Cys1, D-Arg8]-vasopressin. The production of cyclic GMP evoked by
oxytocin
was inhibited selectively by [d(CH2)5, Tyr(OMe)2, Orn8]-vasotocin, an
oxytocin
antagonist. The production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin was inhibited by [beta-mercapto-beta, beta-cyclopentamethylene-propionyl1, O-Me-Tyr2, Arg8]-vasopressin, a selective V1-receptor antagonist. The moderate production of cyclic GMP evoked by [deamino-Cys1, D-Arg8]-vasopressin was inhibited significantly by the V1-receptor antagonist. The peptide antagonists affected only minimally or not at all the production of cyclic GMP evoked by a donor of nitric oxide, SIN-1 (3-Morpholino-Sydnonimine). These observations indicate that 1) neurohypophyseal hormones and tachykinins stimulate the accumulation of cyclic GMP in cultured porcine aortic endothelial cells by increasing the production of endothelial-derived nitric oxide, which in turn enhances the activity of soluble guanylate cyclase; 2) the production of cyclic GMP in response to
oxytocin
is due to activation of oxytocinergic receptors; and 3) the production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin is due mostly to activation of V1-vasopressinergic receptors.
...
PMID:Neurohypophyseal peptides and tachykinins stimulate the production of cyclic GMP in cultured porcine aortic endothelial cells. 217 9
Oxytocin
(OT) has been shown to play a role in the control of physiological PRL release and has been demonstrated to have a direct effect on the pituitary to stimulate PRL secretion. Administration of OT into the third ventricle, however, lowers PRL levels. This reduction could be mediated by either an inhibition of the release of endogenous OT into the hypohysial portal circulation or via an alteration in the release of some other PRL releasing (PRF) or PRL release-inhibiting (PIF) factor. In order to determine if centrally administered OT lowers PRL levels by increasing secretion of dopamine (DA) into the portal circulation, endogenous dopaminergic tone was blocked by injection of the DA antagonist domperidone (DOM). Subcutaneous administration of DOM resulted in elevated PRL levels which could be further augmented by iv infusion of OT (at 0.01 or 0.1 microgram OT/kg.min) or partially, but significantly, reduced by pretreatment with anti-OT antiserum (0.75 ml) indicating that under conditions of DA blockade, OT (which has little PRF activity during conditions of normal dopaminergic tone) can stimulate PRL secretion by a direct pituitary action. Treatment with DOM did not prevent, however, the reduction in PRL levels produced by central administration of OT (2 micrograms). This suggests that the effect of OT to alter PRL secretion when administered into the third ventricle was not mediated via an increase in DA release into the portal circulation. Furthermore, central administration of the OT antagonist CAV-259 (1-deamino-2-D-Trp-4-Val-8-Orn-OT) after DOM treatment resulted in a significant increase in PRL secretion indicating that endogenous levels of OT within the hypothalamus inhibit PRL secretion through a nondopaminergic mechanism. This stimulatory effect of the OT antagonist was not blocked by pretreatment with anti-OT antiserum (iv) which had been demonstrated previously to reduce the PRL surges in lactating mothers and steroid-primed ovariectomized rats, as well as to block the increase in PRL secretion seen after central administration of vasoactive intestinal peptide (VIP). Thus the central effect of OT to alter PRL secretion was probably not due to a change in the release of OT into the portal circulation. Intravenous administration of a VIP antagonist (D-4-Cl-6-Phe-17-
Leu
-VIP, previously demonstrated to be capable of reducing the PRL surge seen in lactating mothers) into DOM-treated rats does not alter PRL levels but blocks the ability of central administration of the OT antagonist CAV-259 to increase PRL levels under these conditions.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Interactions of dopaminergic and peptidergic factors in the control of prolactin release. 229 69
The distribution of
leucine
-enkephalin, methionine-enkephalin, neurotensin, somatostatin, substance P,
oxytocin
, vasopressin, neurophysin II, and serotonin in nerve terminals and fibers of sympathetic autonomic areas of the thoracolumbar (T-L) spinal cord was studied immunohistochemically in cats. Densities of these immunoreactive terminals and fibers were estimated in the intermediolateral nucleus pars principalis (IMLp) and pars funicularis (IMLf), the nucleus intercalatus (IC), and the central autonomic area (CA). Results for
leucine
- and methionine-enkephalin-like immunoreactivity (ENK) were similar and immunoreactivity for vasopressin was not observed. The greatest numbers of terminals and fibers in the IMLp region contained ENK, neurotensin-(NT), and serotonin-like immunoreactivity (5HT); terminals and fibers containing substance P-(SP) and neurophysin II-like immunoreactivity (NP2) were intermediate in number, and those containing somatostatin-(SS) and
oxytocin
-like immunoreactivity (OXY) were generally sparse. In the IC and CA, terminals and fibers containing ENK and NT were dense, those containing SP were moderate, and those containing OXY, NP2, and 5HT were sparsely represented. In the IMLp, where the largest proportion of sympathetic preganglionic neurons (SPN) is found, the greatest concentration of terminals and fibers containing ENK was found in segments T1-T8; for NT these segments were T1-T5 and T11-L1, for SP-C8-T2 and T11-L1, for NP2-T4-T7 and L2 to L3, and for 5HT-T1-T5. Terminals and fibers containing SS and OXY were present in segments C8-T10 and segments C8, T2-T8, T13, and L2 to L3, respectively. These results indicate that while ENK, NT, SP, NP2, and 5HT fibers and terminals are widely distributed throughout the T-L cord, they may influence to a greater degree the SPN in segments where they are present in greater numbers. As SS and OXY were not found at all levels of the IMLp, their functions may be more organ specific.
...
PMID:Segmental distribution of peptide- and 5HT-like immunoreactivity in nerve terminals and fibers of the thoracolumbar sympathetic nuclei of the cat. 241 41
The distribution of
leucine
-enkephalin, methionine-enkephalin, neurotensin, somatostatin, substance P,
oxytocin
, vasopressin, and neurophysin II in cell bodies of sympathetic autonomic nuclei of the thoracolumbar (T-L) spinal cord was studied immunohistochemically in cats after intrathecal administration of colchicine. Neurons containing only enkephalin-, neurotensin-, somatostatin-, and substance P-like immunoreactivity (ENK, NT, SS, SP, respectively) were found in the intermediolateral nucleus pars principalis (IMLp) and pars funicularis (IMLf), the nucleus intercalatus (IC), and the central autonomic area (CA). The size, shape, location, and numbers of the peptide-positive neurons in the IMLp, IMLf, and IC suggested that they were sympathetic preganglionic neurons (SPN). This was confirmed by a combined retrograde tracing/immunohistochemical study showing that most of these neurons at the levels of the T-L cord known to provide preganglionic fibers to the stellate ganglion were SPN. On the other hand, the functional identification of the neurons in the CA is uncertain as neurons were not observed which were both retrogradely labelled and contained ENK, NT, SS, or SP. Immunoreactive neurons in each area were counted in ten sections from each segment from C8 to L4. In the IMLp, the SPN with ENK were greatest in number (up to 25) in segments T4-T7 and L2-L3. The maximum number of SPN containing NT was found in segments T4-T7 (45 neurons). Of the four peptides, neurons containing SS were found in the greatest number (up to 48 in segments T2-T6); neurons containing SP were found in the smallest number (15 or fewer per segment). Few SPN containing each of the four peptides were found in the IC; CA neurons with ENK and NT were also few in number. A comparison of the numbers of immunoreactive neurons in the IML with earlier estimates for the total numbers of SPN in the IML at each level showed that the proportions of IML neurons containing each of the four peptides were fairly consistent throughout the T-L cord, with some exceptions. These results suggest that the innervation of visceral organs is not obviously peptide-specific, although some organs may be innervated by a greater proportion of SPN containing one of these peptides. Finally, the presence of ENK, NT, SS, and SP in SPN suggests that these four peptides act as neurotransmitters in preganglionic pathways to sympathetic ganglia.
...
PMID:Segmental distribution of peptide-like immunoreactivity in cell bodies of the thoracolumbar sympathetic nuclei of the cat. 241 42
The medial preoptic nucleus (MPN) is a sexually dimorphic complex with three major subdivisions. The cell-dense central (MPNc) and medial (MPNm) subdivisions are larger in male rats, while the cell-sparse lateral subdivision (MPNl) occupies a majority of the nucleus in females. In the present study we evaluated the distribution of possible monoaminergic and peptidergic cells and fibers within the MPN, as well as in adjacent regions of the medial preoptic area of the adult male rat. For this, we used an indirect immunohistochemical method with antisera to serotonin (5HT), dopamine beta-hydroxylase (DBH), tyrosine hydroxylase (TH), neuropeptide Y (NPY), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), substance P (SP), neurotensin (NT), corticotropin-releasing factor (CRF), luteotropin-releasing hormone (LRH), somatostatin (SS), thyrotropin-releasing hormone (TRH),
oxytocin
(
OXY
), vasopressin (VAS), adrenocorticotropic hormone (1-24; ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH),
leucine
-enkephalin (L-ENK), and calcitonin gene-related peptide (CGRP). The results suggest that cell bodies and/or fibers crossreacting with all of these putative neurotransmitters are differentially distributed within the MPN. Within the MPNm, the densest plexuses of fibers were stained with antisera to SP and NPY, while moderate densities of fibers were stained with anti-DBH, SS, CCK, CGRP, ACTH, and alpha-MSH, and only a few fibers were stained with anti-5HT, TH, NT, VAS, and L-ENK. Moderate numbers of SP- and L-ENK-immunoreactive cell bodies, and a few SS-, NT-, CRF-, and TRH-stained cell bodies were also found within the MPNm. The MPNc contained a dense plexus of CCK-immunoreactive fibers, as well as a few CRF-immunoreactive fibers. Both fiber types were localized almost exclusively to this subdivision, while most of the others studied here appeared to avoid it selectively. This suggests that there are relatively few inputs to the MPNc, and that they tend to avoid other parts of the nucleus, although moderate densities of DBH- and NPY-immunoreactive fibers were found in both the MPNm and MPNc. The MPNc contained several CCK-immunoreactive cell bodies as well as a moderate number of TRH-stained cell bodies. Both cell types were nearly completely localized to the MPNc. The major inputs to the MPNl studied here appear to be stained with antisera to 5HT and L-ENK, although moderate numbers of NT- and CRF- immunoreactive fibers were also found in this part of the nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Neurotransmitter specificity of cells and fibers in the medial preoptic nucleus: an immunohistochemical study in the rat. 242 28
The distribution of the carbohydrate epitope 3-fucosyl-N-acetyl-lactosamine was investigated on paraffin sections of the normal adult human central nervous system by means of immunohistochemistry, using the mouse monoclonal antibody anti-
Leu
-M1. This antibody is one among many others recognizing this epitope, which is also known as stage specific embryonic antigen I or X-hapten. We found this epitope predominantly localized on astrocytes especially along their numerous cell processes. There was a striking association of immunoreactive astrocytes with intracortical blood vessels and with distinct brain areas.
Leu
-M1-positive oligodendrocytes were present in the white matter with highest densities in the centrum semiovale and lateral pontine regions. Most cells of the ependymal lining, including tanycytes, showed
Leu
-M1 immunoreactivity but there was some topographical variability. Double-labelling experiments revealed that
Leu
-M1-positive glial cells may or may not be immunoreactive to glial fibrillary acidic protein or S-100 protein. The
Leu
-M1 antibody also stained a large number of different sets of neurons from cerebral cortex to spinal cord. Groups of immunostained cells were found in the hypothalamus, dorsal thalamus, ventral and mesial mesencephalic tegmentum, and several lower brainstem regions such as the lateral reticular formation, the raphe nuclei and the pons.
Leu
-M1 immunoreactivity appeared associated to neurochemically specified neuronal cell groups such as the mesencephalic dopaminergic system and the hypothalamic
neurophysin
system. In summary, our study demonstrates a distinct topographical distribution of the
Leu
-M1 epitope in the adult human central nervous system. Its exact functions, however, have not yet been elucidated, but there is evidence for the involvement of this epitope in cell-cell-adhesion and -interaction processes.
...
PMID:Distribution of the carbohydrate epitope 3-fucosyl-N-acetyl-lactosamine (FAL) in the adult human brain. 247 36
We have elucidated the X-ray diffraction structures of the psi[CH2NH] backbone-modified analogs of Z-Pro-
Leu
-Gly-NH2 and t-Boc-Pro-
Leu
-Gly-NH2 (N alpha-protected derivatives of the tripeptide amide representing the C-terminal tail of
oxytocin
) with the "reduced peptide bond" located at the Pro-
Leu
sequence. The comparative results of these pseudopeptides show that conformational properties are similar (i.e., C7 structure at the Pro), whereas the unmodified peptides diverge substantially (i.e., t-Boc-Pro-
Leu
-Gly-NH2 and H-Pro-
Leu
-Gly-NH2 each show type-II beta-bend at the
Leu
-Gly; and Z-Pro-
Leu
-Gly-NH2 shows an open folded structure). The results for t-Boc-Pro psi[CH2NH]
Leu
-Gly-NH2 represent the first unequivocal proof for the existence of a C7 structure in a linear peptide.
...
PMID:Psi [CH2NH] backbone-modified peptides: first unequivocal observation of a C7 structure in a linear peptide. 252 Jul 71
Several neuropeptides were immunohistologically studied in normal human spinal cords. Substance P, methionine-enkephalin,
leucine
-enkephalin, and cholecystokinin positive fibers were found in all cytoarchitectonic layers, with a specific distribution pattern for each peptide. Somatostatin,
oxytocin
, and vasopressin immunoreactivities were restricted to particular spinal layers. Perikarya and proximal dendrites were visualized and classified by comparison with previous Golgi analyses. Substance P was contained in "radiate cells" of layer III, methionine-enkephalin in marginal neurons as well as in layer II "stellate cells," and somatostatin in layer II "islet cells." Several results differed from those reported in other species. Chemical neuroanatomy may provide new insights into the neuronal organization of the human spinal cord.
...
PMID:Substance P, enkephalins, somatostatin, cholecystokinin, oxytocin, and vasopressin in human spinal cord. 258 9
Two genes each encoding a distinct precursor protein to the hormone isotocin and a
neurophysin
-related protein are present in the teleost fish Catostomus commersoni. These precursors are referred to as isotocin 1 and 2. As shown by the polymerase chain reaction technique, both genes lack introns in their protein-coding sequences. Both genes are transcribed giving rise to mRNAs of 920 (isotocin 1) and 1020 (isotocin 2) bases, respectively. Based on the nucleotide sequences, the predicted isotocin precursors contain, besides the hormone moiety, a
neurophysin
-like protein that, in contrast to its mammalian counterpart, is extended at its C-terminus by a peptide which includes a
leucine
-rich core segment. This segment shows similarities to the copeptin of the mammalian vasopressin precursor that is known to possess prolactin-releasing activity. The data imply that the mammalian copeptin sequence was initially part of a larger ancestral
neurophysin
molecule.
...
PMID:Two isotocin genes are present in the white sucker Catostomus commersoni both lacking introns in their protein coding regions. 258 84
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